Theta (Upper) in LaTeX (\Theta)

Where it is used

Uppercase Greek Theta, standard for tight asymptotic bounds and parameter spaces.

Algorithm analysis writes \Theta(n \log n) for a bound that holds both above and below, alongside O and \Omega. Statistics uses \Theta for a parameter space, as in \theta \in \Theta. Physics uses it for the Heaviside step function \Theta(x) and for temperature in some texts. Capital Greek letters are upright in LaTeX; \varTheta gives an italic form if a style calls for it. Do not confuse \Theta with the empty set glyph or with the digit 0 crossed by a bar.

Minimal compilable example

Paste this into an empty .tex file and compile it with pdfLaTeX, XeLaTeX or LuaLaTeX.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
Theta (Upper): $\Theta$

\[ T(n) = 2T(n/2) + \Theta(n) \implies T(n) = \Theta(n \log n) \]
\end{document}

Related symbols

• Iota\iota
• Theta\theta
• Kappa\kappa
• Eta\eta
• Lambda\lambda
• Zeta\zeta

Frequently asked questions

How do I write Theta (Upper) in LaTeX?

Type \Theta in math mode, for example $T(n) = 2T(n/2) + \Theta(n) \implies T(n) = \Theta(n \log n)$. It works in plain LaTeX without loading any package.

Which package do I need for \Theta?

None. \Theta is part of standard LaTeX, so it compiles with nothing in the preamble but the document class.

Can I use \Theta in text mode, or only in math mode?

Only in math mode. Outside $...$ LaTeX stops with "Missing $ inserted", so write $\Theta$ in running text. If you only need the glyph in text, paste the Unicode character Θ instead (with XeLaTeX or LuaLaTeX and a font that has it).